Prosthetic devices such as prosthetic hands, prosthetic partial hands and prosthetic fingers can have their movements controlled by electromyographic (EMG) signals. Such EMG signals may be measured by placing electrodes on the residual limb, or stump, of a human subject or patient. The EMG signals are then processed to control actuators that result in the of movement of a prosthetic device. Users of such myoelectric prosthetic devices typically need practice to control their muscles in order to generate the optimum EMG signals as measured by the electrodes. A patient can learn to control the intensity, pattern and timing of activation of one or more of their muscles in order to trigger the EMG signal. This practice may be time consuming, depending on the particular patient.
Prosthetic devices can be computer controlled so that they respond to complex patterns and timings of EMG signals. In order to use a limited set of control signal patterns to control a large number of possible movements (or movement features) of a prosthetic device, a profile may be used. A profile is an assignment of particular set of control signals, such as caused by a pattern of triggers (for example hold open, co-contract, double impulse and triple impulse) to respective movement features of the prosthetic device. For example, for a prosthetic hand the movement features are called grip features and may include, but are not limited to, pinch open, pinch closed, thumb open, thumb closed, “three way chuck” pinch open or closed, index point, natural hand and thumb parking. The profile, once set up by a patient, can thus be used to translate control signals triggered by muscle activity in the patient's residual limb into movements to particular selected positions (features) of the prosthetic device.
When a patient receives a new prosthetic device it takes them time to learn how to control the device. The procurement, fitting and manufacturing typically results in a long delay from the initial meeting with the prosthetist to the time when the patient can begin training to use the prosthetic by practicing its use. One problem with this is that a patient cannot use their prosthetic device with full control starting on the day that they eventually do receive it. Another problem is that when the training, which involves practicing using muscles in the residual limb, begins after the prosthetic device is delivered, the patient's muscles can change in shape as they develop in response to the training. This has the unfortunate effect of making the socket that mounts on the residual limb and onto which the prosthetic device is connected, cease to fit comfortably. This can result in another cycle of fitting, manufacture and delivery of a revised socket, thus delaying comfortable use of the prosthetic with full control. In the worst case, if the socket has to be taken away for remanufacture because it no longer fits, then the patient is unable to use the prosthetic device in the absence of the socket. Another problem is that the patient can get out of practice and may lose muscle tone when the prosthetic device is sent away for repair or servicing.
It would be advantageous to overcome at least some of the problems described above.